1. Field of the Invention
The present invention relates to an input device which uses a touch panel arranged on a display device such as a liquid crystal or organic electro-luminescent (EL) display device, the touch panel used to enter information by pressingly operating the touch panel with a finger or a stylus in response to contents displayed on the display device.
2. Description of the Related Art
As display devices, flat-panel display devices including liquid crystal display devices and organic EL display devices are used for numerous electronic appliances. A touch panel as an input device for such an electronic appliance is superimposed on a surface of a flat-panel display device, so that information is entered into the electronic appliance by touching the touch panel with a finger or the like in response to the display on the display device.
Such an input device using the touch panel often employs a structure in which a touch panel 104 is supported between a liquid crystal display 105 and a front panel 102 as well as a fixing frame 103, as shown in Japanese Patent Application Publication No. 2008-70762. As shown in FIG. 13, in this structure, the peripheral portion of the touch panel 104 is held by the front panel. For this reason, the front panel juts out in a frame-like shape, whereas the peripheral portion of the touch panel always needs to be superimposed on the front panel. Furthermore, operation switches S1 to S5, such as a power supply switch and control switches, are provided in the front surface of a lower side portion of the front panel 102.
In addition, as shown in Japanese Patent Application Publication No. 2005-242501, there is employed a structure in which a touch panel is supported on a portion of a case 205 around a window 251 by use of a two-sided adhesive tape 208. In this structure as well, as shown in FIG. 14, the case 205 itself juts out in a frame-like shape on the peripheral portion of the touch panel, whereas the peripheral portion of the touch panel always needs to be covered with the case 205.
Moreover, there has been so far no input device using a touch panel provided with both an area for displaying information and operation switches including a power supply switch.
In the conventional input device using a touch panel, as described above, the front panel or the case juts out in a frame-like shape on the peripheral portion of the touch panel, whereas the front surface of the touch panel is slightly set back from the front panel or the case. For this reason, the front panel or the case hinders the touch panel from being touched. A problem with the conventional input device is that, particularly when a marginal portion of the touch panel needs to be touched, an operation switch provided in the side portion of the front panel or the case may be operated by mistake.
Another problem with the conventional input device using a touch panel is that the touch-panel supporting structure imposes restriction on the design, because the front panel or the case inevitably juts out in a frame-like shape.
Yet another problem with the conventional input device using a touch panel is that: the boundary between the peripheral portion of the touch panel and the frame-shaped portion of the front panel or the case becomes soiled by finger grime and dust, and becomes dirty as the input device is used for a longer time.
Still another problem with the conventional input device using a tough panel is limitation on the size of the input device and latitude in the design of the surroundings of the input device, because the input device is designed based on the concept that a portion of the touch panel corresponding to each operation switch displayed on the liquid crystal display or the like is touched for an input operation, and is provided with other operation switches, which are different from the operation switch displayed on the liquid crystal display or the like, independently of the touch panel.